First Russell please don't yell. (all caps is considering yelling).
Please get off the idea of a vacuum as this engine setup with a fuel tank mounted carburetor and the venting done by the fuel caps prevents this. The only vacuum going on is when the engine is pulling in fuel and air mix through the carburetor ventura which operates the fuel pump diaphragm
As for the fuel leakage there can be several possibilities. There is a gasket and fuel pump diaphragm between the carburetor and the fuel tank that can goes bad, fuel can be leaking, the tank itself, or even the carburetor can warped from someone over tightening the the screws.
Now verify it is ignition problem or carburetion problem when the engine will not start remove the spark plug and squirt a little gas into the engine via the plug hole, replace the plug, and try starting. If it starts then it is a fuel supply problem; otherwise, it is ignition. Now if the engine has a lot hours on it then it could valve related but this a fairly new on the market.